Adjustable spring hold-down for radio tubes



Jan. 30, 1951 L. T. HOLDEN ADJUSTABLE SPRING HOLD-DOWN FOR RADIO TUBES Filed Jan. 8, 1946 FIG. 2

FIG.4

FIG.3

FIG.5

FIG.7

FIG.6

INVENTOR LAWRENCE T. HOLDEN ATTORNEY Patented Jan. 30, .1951

UNITED STATES PATENT OFFICE ADJUSTABLE. SPRING HOLD-DOWN-FOR RADIO TUBES Lawrence T. Holden, Jamaica Plain,l'Mass., as-

signor, by mesne assignments, to the United States ofAmerica. as represented by-the Secretary of the Navy Application January 8, 1946, Serial No. 639,890

-3 Claims. -1

This invention in general relatesto clamping apparatus, and in particular to a clamp for hold ing vacuum tubes rigidly in their sockets.

Vibration has a detrimental effect on the performance of vacuum tubes because it alters the distance between elements within the tube. Since it is virtually impossible to maintain socket holes to such a close fit that there is no play between their Walls and the *tubes pins, some external stabilizing deviceisnecessar-y for tubes subjected A primar object of the present invention is to generally improve tube clamps by eliminating the foregoing difficulties. Another object of this invention is to provide a clamp for holding an electron tube that may be operated at the top. of the tube. These and other objects will be apparent from the following specification when taken with the accompanying drawings, in which:

Fig. 1 shows a complete tube clamp assembly in accordance with'the invention holding an electron tube;

Fig, 2 shows the spring clamp member of the apparatus of Fig. 1;

Figs. 3, 4 and 5 show top, side, and section views respectively of the friction cap for gripping the top of the tube; and

Figs. 6 and '7 show bottom and side views respectively of a mounting lug for holding the spring member of Fig. 2.

In the drawings, and more particularly Fig. l

the complete clamp comprises two supporting lugs IS with foot flanges l4 (shown in Fig. 7) for attachment to a suitable base. Each lug I3 has a series of holes I5 which may be about apart, into an opposite pair of which may be clipped the legs of a generally U-shaped spring member I6. The spring member I6 is disposed over the top of an electron tube I i or other article to be clamped in position, and spring-action of the indented portion I2 of said member I6 provides desired pressure. A friction cap I I, attached as for example by a rivet 24, to the aforementioned indented portion I2 of the spring member I6, firmly grips the top of the tube II.

As shown in Fig. 6, the foot flange I4 of each lug I3 may be turned in toward the socket holding the electron tube so that the samescrew -holes,'drilled in'the chassis. for the socket attachment, may a1so be used for the clamp. Small tapering ears I8 project at an angle from the base of the lug for additional support and to strengthen thelug against the diagonal strain caused when thespring member I6 is clamped over the tube. According to the height of the tube II, one of a pluralityof pair of holes I5 in the vertical members of the lugs I3 is selected for attachment of the spring member I6. In a particular case, if the lugs 53 are too high, any

excess length of the Vertical portion may be cut off.

The spring member I6, illustrated in detail in Fig. 2, is preferably made of spring tempered carbon steel, but maybe made of other suitable .materials if desired. These members I6 may be .made in various leg lengths in order that the clamp may be used with-tubes of different sizes.

On each leg ofithe spring member I6 there is a clip or hook I9, and below it a substantially rounded projection 20, so spacedthat when the clip I9 isv hooked into one of the 110195 I5 of the lug I3, the projection 20 will center in thenext lower hole. A narrow flange 2| stiffens each end of the spring member I6 between the clip I9 and the projection 20,

The friction cap I'I, illustrated in Figs. 3 to 5, inclusive, may be made in various sizes to accommodate tubes of difierent dimensions. These caps I1 are preferably made of cadmium plated rolled steel, and coated on their inside surface with resilient friction providing material 23, as for example, neoprene, to provide friction surface against the tube. Two edge flanges 22 are provided as comfortable finger grips.

Among the advantages of this tube clamp, as may be seen from the foregoing description, is that it requires about one-half inch less space between tubes than the old type bracelet clamp. It also offers the additional advantage of being workable at the top of the tube instead of the bottom, which tends for easy operation.

The invention described in the foregoing speci" fication need not be limited to the details shown, which are considered to be illustrative of one form the invention may take.

What is desired to secure by Letters Patent and claim is:

1. Apparatus for holding an electron tube firmly in a socket comprising, first and second elongated lugs each apertured along the longitudinal dimension thereof and provided with a foot for engaging said socket, the elongated portions of said lugs extending toward the top of an electron tube when said tube is in place in said socket, a substantially U-shaped spring member bent inversely at its center and having a hook on each of its free ends for engaging in one of the apertures of each of said lugs, said hooks pivotally securing said spring member to said lugs, a rounded projection on each of said free ends of said spring member for engaging an adjacent aperture in the same lug, a friction cap attached to the inversely bent portion of said spring member, said cap being coated with friction material to grip the top of said tube when said spring member is swung into position over said tube, said engaging projections then preventing said spring member from changing position, whereby said tube is held in said socket.

2. Apparatus for holding an electron tube firmly in a socket comprising first and second elongated lugs each apertured along the longitudinal dimension thereof, said lugs being provided with a footfor engaging said socket and further provided with a stiffening flange on the upright portion thereof, the elongated portion of said lugs extending toward the top of an electron tube when said tube is in place in said socket, a substantially U-shaped spring member bent inversely at its center and having a hook on each of its free ends for engaging one of the apertures of each of said lugs, said hooks pivotally securing said spring member to said lugs, a rounded projection on each of said free ends of said spring member for engaging an adjacent aperture in the same lug, and a stiffening flange on each of said free ends in the region of said hook and said projection, a friction cap attached to the inversely bent portion of said spring member, said cap being coated with friction material to grip the top of said tube when said spring member is swung into position over said tube, said engaging projections then preventing said spring member from changing position, whereby said tube is held in said socket.

3. Adjustable apparatus for holding an electron tube firmly in a socket comprising first and 4 second elongated lugs each having at least three apertures along the longitudinal dimension thereof, said lugs being provided with a foot for engaging said socket and further provided with a stiffening flange on the upright portion thereof, the elongated portion of said lugs extending toward the top of an electron tube when said tube is placed in said socket, a substantially U-shaped spring member bent inversely at its center in the plane of said U and having a hook on each of its free ends for detachably and pivotally engaging one of the apertures of each of said lugs, the apertures engaged by said'hooks being determined by the height of the electron tube to be held, a rounded projection on each of said free ends of said spring member for engaging an adjacent aperture in the same lug, and a stiffening flange on each of said free ends in the region of said hook and said projection, a friction cap attached to the inversely bent portion of said spring member, said cap being coated with friction material to grip the top of said tube when said spring member is swung into position over said tube, said engaging projection then preventing said spring member from changing position, whereby said tube is held in said socket.

LAWRENCE I. HOLDEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,169,497 Kohlrnann Jan. 25, 1916 1,429,952 Kearney Sept. 26, 1922 1,568,995 Benjamin Jan. 12, 1926 1,579,832 Patche Apr. 6, 1926 1,616,176 Bremer Feb. 1, 1927 1,637,864 Kolster Aug. 2, 1927 1,665,095 Henry Apr. 3, 1923 1,897,852 Metz Feb. 14, 1933 1,985,459 Pratt Dec. 25, 1934 2,449,646 Emde Sept. 21, 1948 

